Finny is the only character in the novel for whom Knowles does not provide a last name. Unlike Gene Forrester, whose name offers two different meanings (well-born and hardy), Finny's character needs no qualification: Finny is just Finny.
True to his aquatic-sounding name, Finny lives in action like a fish in water — moving, playing, challenging others to join him. Finny's game of blitzball, for example, expresses his essential nature with its spontaneous style of play and its rules made up on the run.
For all of his immediacy, though, Finny appears to the reader only from Gene's perspective. As narrator, Gene shares his own feelings while observing Finny's actions and speech, but he never enters his friend's thoughts. For example, Gene (and the reader) learns only late in the novel that Finny desperately wants to enlist in the military — any military — and that his fantasy about the fake war simply represents a way of hiding his pain.
Because Gene focuses so much on Finny, Finny himself assumes a paradoxical role in the story — neither narrator nor protagonist, yet still clearly central to the novel. And while most fictional characters come alive because they change over the course of the story, Finny's vitality emerges instead from the fact that he remains the same — his fundamental characteristics consistent from beginning to end.
From his clothes — especially that pink shirt — to his daring jumps from the tree, Finny flouts all the prep school conventions as the classic rebel in an overwhelmingly conformist world. Yet Finny's actions — even his most dangerous antics — spring up spontaneously, out of a natural enjoyment of life, without a trace of deviousness or vindictiveness, and this innocence informs his view of everyone else as well. Finny, for example, cannot imagine that Gene might envy him his easy success as an athlete, nor does he suspect that his friend's secret animosity might suddenly erupt in violence.
As the innocent in this story of Eden lost through human weakness and war, Finny emerges finally as a kind of Christ-like figure. Through the sacrifice of his suffering and death, Finny redeems Gene, offering his friend — in their essential doubleness — the promise of a better self.